Process of extracting alkali from minerals.



S. PEACOCK. PROCESS OF EXTRACHNG ALKALI FROM MINERALS. APPLICATION man suns-2a, 191s.

1,202.21'5. I Patented Oct. 24,1916;

Sarfiuel Pea c0010, 5;; /z wkaiuw almxmow UNITED STATES PANT GFFICE.

SAMUEL PEACOCK, OF PHILADELPHIA, PENNSYLVANIA, ASSIGNOR, BY MESNE ASSIGN- MENTS, T0 MARDEN, ORTH & HASTINGS 00., IN 0., OF NEW YORK, N. Y., A CORPO- RATION OF MAINE.

PROCESS OF EXTRAC'I'ING ALKALI FROM MINERALS.

Specification of Letters Patent.

Patented Oct. 24, 1916.

Application filed June 28, 1915. Serial N 0. 36,827.

1 '0 all whom it may concern:

Be it known that I, SAMUEL PEACOCK, a citizen of the United States, residing at Philadelphia, in the county of Philadelphia and State of Pennsylvania, have invented certain new and useful Improvements in Processes for Extracting Alkali from Minerals; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

' This invention relates to a process of extracting potash from feldspar and other naturally occurring minerals, such as muscovite, leucite, etc., and has for its object to provide a method which will be more eilicient and less costly in its operation than those which have been heretofore proposed.

Withthese and other objects in view the invention consists in the novel steps and combinations of steps constituting the invention, all as will be more fully hereinafter disclosed and particularly pointed out in the claims.

Referring to the accompanying drawing forming a part of this specification, in which the figure is a diagrammatic sectional elevational view of a furnace suitable for carrying out the invention, 1 indicates any suitable support for surrounding and steadying any suitable stack 2, supported from the base or hearth 3,-providing a space or crucible 4 for the molten bath, and having the upper tap hole 5, and lower tap hole 6 leading from near the bottom of said crucible.

7, 8, and 9 represent electrodes for any suitable current, but I prefer to use one of the three phase type.

The stack 2 is restricted near its bottom as at 10, in order that the charge 11 may be fed into the crucible 4, and there subjected tov the melting action of the current. The electrodes are conveniently regulated by any suitable means as by the racks 12 and the pinions 13.

14 and 16 represent lead'wires.

The top of the stack is preferably closed as by means of the valve mechanism or hell 17, and thwefore any gases liberated by the "reaction are substantially prevented from freely escaping.

In carrying out the process, the charge 11 .ever, Imay instead of sulfuric acid, add

other materials is suitably introduced into 5 the stack 2, through the bell 17, and fills the crucible. The current is preferably started in the usual way by making a contact between theelectrodes in the beginning as by carbon or other transitory connections, and then the electrodes are gradually pulled apart until the necessary temperature is attained. The temperature will rise to about say 14:00 (1, or 1500 C., whereupon the rock charge material will be found to be sufficiently fluid to readily flow from the tap hole 5, and as it leaves said tap hole, I may subject it to a blast of air, or I preferably deliver the molten rock directly into a stream of water which converts the molten mineral into an amorphous and very porous condition. The molten mineral being thus reduced to a solid and amorphous condition, it becomes soluble to the action of acids or alkalis, and I thereupon suitablydigest the same preferably with an acid, such for example as sulfuric acid, in order to forni a the of the alkali metal present, and thus form @385 paste like mass, which may be stored as prd duced, in a suitable bin for say 24 hours or 48 hours, whereupon the reaction between the alkali metal of the rock and the sulfuric acid proceeds to a substantial completion and the mass cools down. The mass becomes solid in this condition, and can be sold for fertilizer purposes; or if it is desired to extract the potash, the latter may be leeched or; with water by any Well known and suitaL- method thus recovering an alkali sul-. fate as a final product.

Instead of treating the amorphous mass with sulfuric acid as just disclosed, howwater and commercial acid hosphate, which latter consists of mono-ca cium phosphate and other materials, such as sulfate of lime, etc.- When thus treated, the mass is also allowed'to stand for the same length of time, whereupon a double decomposition takes place; the mono-calcium phosphate reacting with the alkali metal silicate, and forming' calcium silicate and alkali metal phosphate. After this latter treatment, the mass will be in a solid form and may be sold for fertilizer purposes as before; or the mass may be later treated with water, whereby the alkali metal phosphate will be dissolved out leaving the calcium silicate behind. The final alkali metal phosphate product thus produced may then be concentrated to any suitable degree,

or crystallized into the solid form.

Instead of proceeding as above, I may digest the amorphous mineral mass with a solution of an alkali metal caustic, or carbonate such as KOH or K CO In adding the alkali, care should be taken to supply only an amount which when combined with the alkali metal already present will be sufficient to react with all of the silica present to form a soluble silicate, but not sufficient to combine with any of the almuina present. By this means, the alumina remains in an insoluble form and may be separated from the silicates by filtration; it further forms a valuable by-product. To recover the alkali metal from the soluble silicate, two methods may be pursued. I may add carbonic acid gas, C0 but such method would cause the silica to come down in a gelatinous state which is very diiiicult to filter. But on the other hand, this converts the alkali metal to a carbonate, and the silica ultimates in a very pure hydrate which has many commer cial applications. The second method is the one I prefer, and it consists in adding milk of lime to the alkali metal solution which forms an insoluble silicate of calcium, and liberates the alkali hydrate as a final prodnet. These latter two compounds are easily separated by ordinary filtration.

ilhe apparatus herein disclosed forms no part of the present invention.

It is an important feature of this invention that the mineral is melted as such, without any substantial admixture of carbon, basic fluxes, or other materials, for should such additions be made to the charge, chemical changes would occur which would permit the contained alkali metal in one form or another to escape by volatilization. Even without such additions a greater or less volatilization of the alkali metal in some form takes place owing to the temperature being sufliciently high to make a very fluid melt,

and owing to there being some carbon unavoidably consumed at the electrodes. But such volatilized alkali condenses on the upper parts of the charge, and is brought back to the molten bath. Further this ,volatilization of the alkali metal is greatly hindered owing to the furnace being closed, and to the consequent excessive partial pressure of the alkali in a gaseous state which tends to pref vent furtlier volatilization of said alkali.

It is obvious that those skil :l in the art may vary the details of the invention without departing from the spirit thereof, and therefore I do not wish to be limited to the above disclosure except as may be required by the claims.

What I claim is 1. The process of extracting potassium in the form of compounds from minerals containing the same, which consists in melting said minerals in a closed furnace to produce an excessive partial pressure of the volatilized alkali; converting the -molten minerals into an amorphous condition soluble in alkalis; and treating said amorphous mass with a quantity of an alkali only sufficient when added to the alkali metal naturally present to react with all the silica contained in the mass, to form a soluble alkali metal silicate; substantially as described.

2. The process of extracting potassium in the form of compounds from minerals containing the same, which consists in melting said minerals while maintaining an excessive partial pressure of the evolved alkali; converting the molten minerals into an amorphous condition soluble in alkalis; treating said amorphous mass with a solution ofan alkali only sufficient when added to the alkali metal naturally present to react with all the silica contained in the mass, to form a soluble alkali metal silicate; separating said soluble alkali silicate from the alumina present by filtration; and treating the filtrate thus obtained with milk of lime to form an insoluble calcium silicate and an alkali metal hydrate; and finally separating out the said hydrate from the said silicate; substantially as described.

3. The process of extracting potassium in the form of compounds from minerals containing the same, which consists in melting said minerals in. a closed furnace to produce an excessive partial pressure of the volatilized alkali; and treating said amorphous mass with a quantity of an alkali onlv suflicient when added to the alkali metal naturally present, to react with all the silica contained in the mass, to form a soluble alkali metal silicate; substantially as de scribed.

4. The process of extracting potassium in the form of a compound from minerals containing the same which consists in converting said minerals into an amorphous condition soluble in analkali; and treating said amorphous mass with a quantity of said alkali in solution sufficient only when added to the alkali metal present to reactwith all the' silica contained in the mass to form a soluble alkali metal silicate, substantially as described.

5. The process of extractizg potassium in the form of a compound from minerals in an amorphous condition containing the 130 same, which consists in treating the said 5 rally present to react with all the silica contalned in the mass, to form a soluble alkali metal. silicate; separating said soluble alkali silicate from the alumina present by filtration; treating the filtrate thus obtained with milk of lime to form an insoluble calcium silicate and an alkali metal hydrate; and,

said minerals; maintaining over the molten mass an excessive partial pressure of the alkali metal to prevent said metal from escaping; converting the molten minerals into an amorphous mass soluble in alkalis; and adding'to said mass a quantity of an alkali onlysufiicient when-combined with the alkali metal present to react with all the silica contained in the mass to form a soluble alkali metal silicate, substantially as described.

In testimony whereof I aflix'my signature, in presence of two witnesses.

SAMUEL PEACOCK. Witnesses:

T. A. WITHERSPOON, J. H. SIGGERS.

Qoples of this patent may be obtained for five cents each, by addressing the "commissioner of Patents.

Washington, I). 0. 

